Toon Ramp on point lights

Hi there,
I'm trying to achieve a lighting effect similar to the one implemented in Tomb Raider Go.
It's like this:



Which it does, apparently is to do a ramp on a point light. I guess that's achieved via a shader, but the ones I tried (like the awesome JMO Toon) don't react like that to light.

Do you have any advice about what I can look into? I'm a newbie with shaders, but I can definitely learn something new here.

Thanks!

 

looks like a basic diffuse with light attenuation. for the light banding